To understand fully any country's political system, one needs to understand something of its history. This is especially true of the United Kingdom because its history has been very different from most other nations and, as a result, its political system is very different from most other nations too.

Like its (unwritten) constitution, the British state evolved over time. We probably need to start in 1066 when William the Conqueror from Normandy invaded what we now call England, defeated the Anglo-Saxon King Harold and established a Norman dynasty. The Normans were not satisfied with conquering England and, over the next few centuries, tried to conquer Ireland, Wales and Scotland. They succeeded with the first two and failed with the last despite several wars over the centuries.

By one of those ironical twists of history, when Queen Elizabeth of England died in 1603, she was succeeded by her cousin James VI, King of Scots who promptly decamped from Edinburgh and settled in London as King James I of England while keeping his Scots title and running Scotland by remote control. Regal pickings were more lucrative in his southern capital.

A century later the Scottish economic and political elite bankrupted themselves on the Darien Scheme and agreed to a scheme of Union between England and Scotland to make themselves solvent again and so Great Britain with one Parliament based in London came into being. The Irish parliament was abolished in 1801 with Ireland returning members to Westminster and the new political entity was the United Kingdom of Great Britain and Ireland. The southern (Catholic) Irish never reconciled themselves to being ruled by the English and rebelled in 1916 and gained independence in 1922. The northern (Protestant) Irish did not want independence and so the United Kingdom of Great Britain and Northern Ireland arrived. Not a snappy name.

Meanwhile, although the Normans were the last to mount a successful invasion of the country, there were plenty of other plans to conquer the nation, notably the Spanish under King Philip II in 1588, the French under Napoleon in 1803-1805, and the Germans under Hitler in 1940. None succeeeded.

Furthermore, in recent centuries, Britain has not had a revolution of the kind experienced by so many other countries. Some might argue that the English Civil War (1642-1651) was the nation's revolution and - athough it was three and a half centuries ago - it did bring about a major shift in power, but the main constitutional consequence - the abolition of the monarchy - only lasted 11 years and the Restoration of the Monarchy has so far lasted 350 years (although it is now, of course, a very different monarchy). There was a time in British history which we call the Glorious Revolution (1688) but it was a very English revolution, in the sense that nobody died, if a rather Dutch revolution in that it saw William of Orange take the throne.

So the British have never had anything equivalent to the American Revolution or the French Revolution, they have not been colonised in a millennium but rather been the greatest colonisers in history, and in neither of the two world wars were they invaded or occupied.

HOW HISTORY HAS SHAPED THE POLITICAL SYSTEM

The single most important fact in understanding the nature of the British political system is the fundamental continuity of that system. For almost 1,000 year, Britain has not been invaded or occupied as the last successful invasion was in 1066 by the Normans. Is this true of any other country in the world? I can only think of Sweden.

This explains why:

almost uniquely in the world, Britain has no written constitution (the only other such nations are Israel & New Zealand)

the political system is not neat or logical or always fully democratic or particularly efficient

change has been very gradual and pragmatic and built on consensus.

To simplify British political history very much, it has essentially been a struggle to shift political power and accountability from the all-powerful king - who claimed that he obtained his right to rule from God - to a national parliament that was increasingly representative of ordinary people and accountable to ordinary people. There have been many milestones along this long and troubled road to full democracy.

A key date in this evolution was 1215 when King John was forced to sign the Magna Carta which involved him sharing power with the barons. This is regarded as the first statement of citizen rights in the world - although Hungarians are proud of the Golden Bull of just seven years later.

The so-called Model Parliament was summoned by King Edward I in 1295 and is regarded as the first representative assembly. Unlike the absolute monarchs of other parts of Europe, the King of England required the approval of Parliament to tax his subjects and so, then as now, central to the exercise of power was the ability to raise funds.

The bicameral nature of the British Parliament - Commons and Lords - emerged in 1341 and the two-chamber model of the legislature has served as a template in very many other parliamentary systems.

The Bill of Rights of 1689 - which is still in effect - lays down limits on the powers of the crown and sets out the rights of Parliament and rules for freedom of speech in Parliament, the requirement for regular elections to Parliament, and the right to petition the monarch without fear of retribution.

It was the 19th century before the franchise was seriously extended and each extension was the subject of conflict and opposition. The great Reform Act of 1832 abolished 60 'rotten', or largely unpopulated, boroughs and extended the vote from 400,000 citizens to 600,000, but this legislation - promoted by the Whigs (forerunners of the Liberals) - was only carried after being opposed three times by the Tories (forerunners of the Conservatives). Further Reform Acts followed in 1867 and 1884. It was 1918 before the country achieved a near universal franchise and 1970 before the last extension of the franchise (to 18-21 year olds).

Another important feature of British political history is that three parts of the United Kingdom - Scotland, Wales and Northern Ireland - have a special status and have local administrations with a wide range of responsibilities. However, England - which represents about 84% of the total UK population of around 65 million - does not have a clear and strong sense of regionalism. So the British political system does not have anything equivalent to the federal system of the 50 states in the USA. The nature of this (dis)United Kingdom took on a new form in the General Election of May 2015 when the Scottish National Party won 56 out of 59 seats in Scotland.

The final important part of British political history is that, since 1973, we have been a member of what is now called the European Union (EU). This now has 28 Member States covering most of the continent of Europe. Therefore the UK Government and Parliament are limited in some respects by what they can do because certain areas of policy or decision-making are a matter for the EU which operates through a European Commission appointed by the member governments and a European Parliament elected by the citizens of the member states. British membership of the EU has been an especially controversial issue for the Conservative Party and, in the General Election of May 2015, the victorious Conservatives promised an in/out referendum by the end of 2017.

The year 2015 is a special year for the British Parliament as it will be the 750th anniversary of the de Montfort Parliament (the first gathering in England that can be called a parliament in the dictionary sense of the word), along with the 800th anniversary of the Magna Carta, the document that set the scene for the later 1265 de Montfort Parliament.

THREE ARMS OF THE STATE

The British political system is headed by a monarchy but essentially the powers of the monarch as head of state - currently Queen Elizabeth II - are ceremonial. The most important practical power is the choice of the Member of Parliament to form a government, but the monarch follows the convention that this opportunity is granted to the leader of the political party with the most seats in the House of Commons or who stands the best chance of commanding a majority in a vote of confidence in the Commons.

Although any remaining powers of the monarchy are largely ceremonial, the Royal Family does have some subtle and hidden influence on the legislative process because of a little-known provision that senior royals - notably the Queen and her eldest son the Prince of Wales - have to be consulted about legislation that might affect their private interests and given the opportunity to have such legislation amended.

Traditionally the choice of monarch has been determined on the hereditary and primogeniture principles which means that the oldest male child of a monarch was the next in line to the throne. Under the terms of the Act of Settlement of 1701, the monarch and the monarch's spouse could not be Catholics because the UK monarch is also the Head of the Church of England. In 2015, the primogeniture principle was abolished, so that the next in line can now be a female eldest child, and the monarch can marry a Catholic but not himself or herself be one.

In classical political theory, there are three arms of the state:

The executive - the Ministers who run the country and propose new laws

The legislature - the elected body that passes new laws

The judiciary - the judges and the courts who ensure that everyone obeys the laws.

In the political system of the United States, the constitution provides that there must be a strict division of powers of these three arms of the state, so that no individual can be a member of more than one. So, for example, the President is not and cannot be a member of the Congress. This concept is called 'separation of powers', a term coined by the French political, enlightenment thinker Montesquieu. This is not the case in the UK where all Ministers in the government are members of the legislature.

THE U.K. PARLIAMENT

The British Parliament is often called Westminster because it is housed in a distinguished building in central London called the Palace of Westminster.

The British Parliament - like most in the world - is bicameral, that is there are two houses or chambers. The only exceptions to this practice around the world are some small countries such as Finland, Israel and New Zealand.

The House of Commons

This is the lower chamber but the one with the most authority. I worked there as a Research Assistant to Merlyn Rees MP, then Labour's Opposition spokesperson on Northern Ireland, from 1972-1974.

The House of Commons sits each week day for about half of the weeks of the year. The precise hours of sitting are:

Monday 2.30 - 10.30 pm

Tuesday 2.30 - 10.30 pm

Wednesday 11.30 am - 7.30 pm

Thursday 10.30 am - 6.30 pm

Friday 9.30 am - 3 pm

The Commons is chaired by the Speaker. Unlike the Speaker in the US House of Representatives, the post is non-political and indeed, by convention, the political parties do not contest the Parliamentary constituency held by the Speaker.

The House of Commons currently comprises 650 Members of Parliament or MPs (the number varies slightly from time to time to reflect population change). This is a large legislature by international standards. For instance, the House of Representatives in the USA has 435 seats but, of course, each of the 50 US states has its own legislature. Before the General Election of 2010, the Conservative Party said that it wished to reduce the number of Commons seats by around 10% (65 seats) and the Liberal Democrats said that the Commons should be reduced by 150 MPs. The Coalition Government of 2010-2015 passed legislation to reduce the number from 650 to 600, as part of a wider change to the number and size of constituencies, but Parliament blocked the process of redrawing boundaries that is necessary before an General Election can be held with fewer seats.

Rather oddly (but deliberately), there is insufficient seating capacity in the chamber of the House of Commons for all the MPs. Members do not sit at desks (like most legislatures) but on long, green-covered benches and there is only seating capacity for 437 MPs out of the total of 650. The origin of this strange arrangement is that the Commons first home was the medieval St Stephen's Chapel in the Palace of Westminster which could only fit around 400 Members.

Equally odd is that Members vote (votes are called 'divisions') by physically walking through one of the two lobbies which run along the side of the Commons chamber. These lobbies are the 'aye' lobby and the 'nay' lobby. This archaic procedure means that votes take a long time to conduct and it is not unknown for a member accidentally to walk into the wrong lobby. The votes are counted by 'tellers' who then return to the chamber to announce the numbers to the Speaker.

Each member in the House of Commons represents a geographical constituency. Typically a constituency would have around 60,000-80,000 voters, depending mainly on whether it is an urban or rural constituency. The largest constituency in the country is the Isle of Wight with around 110,000 electors, while the smallest is Na h-Eileanan an Iar (formerly known as the Western Isles) with an electorate of only arouind 22,000. The Coalition Government of 2010-2015 intended to make the size of constituencies more equal in terms of electors, but so far the legislation has not been implemented.

Every citizen aged 18 or over can vote once in the constituency in which they live. Voting is not compulsory (as it is in Australia). In the last General Election of May 2015, 66.1% of the electorate actually voted. Most democratic countries use a method of election called proportional representation (PR) which means that there is a reasonable correlation between the percentage of votes cast for a particular political party and the number of seats or representatives won by that party. However, much of the Anglo-Saxon world - the USA, Canada, and the UK but not Australia or New Zealand - uses a method of election called the simple majority system or 'first past the post' (FPTP). In this system, the country is divided into a number of constituencies each with a single member and the party that wins the largest number of votes in each constituency wins that constituency regardless of the proportion of the vote secured. The simple majority system of election tends to under-represent less successful political parties and to maximise the chance of the most popular political party winning a majority of seats nationwide even if it does not win a majority of the votes nationwide.

Until recently, in the UK (unlike many countries), there was not fixed term parliaments. A General Election - that is, a nationwide election for all 650 seats - was held when the Prime Minister called it, but the election could not be more than five years after the last one and it was usually around four years after the last one. I fought the General Elections of February 1974 and October 1974 as the Labour candidate for the north-east London constituency of Wanstead & Woodford. The Coalition Government of 2010-2015 passed legislation to provide for fixed five-year parliaments which means that the next General Election is scheduled for May 2020.

The last General Election was held in May 2015 and the result was as follows:

Conservative Party: 331 seats (up 24) with 36.9% of the vote

Labour Party: 232 seats (down 26) with 30.4% of the vote

Scottish National Party: 56 seats (up 48) with 4.7% of the vote

Liberal Democrat Party: 8 seats (down 49) with 7.9% of the vote

Other parties: 23 seats (down 3) with 20.1% of the vote

Total turnout nationwide was 66.1% up 1.0% on 2010

Note 1: In practice, the Speaker - notionally Conservative - is not counted against any political party because he is required to be neutral.

Note 2: In Northern Ireland, Sinn Fein - which won four constituencies - does not take its seats.

Note 3: The 2015 election was officially the least proportional result in British history. If there had been an exactly proportional result, 24.2% of MPs would be different.

This is the upper chamber but the one with less authority. Its main roles are to revise legislation and keep a check on Government by scrutinising its activities. Since 1911, its power to block "money bills" is limited to one month and its power to block other bills is limited to one session, so ultimately it cannot block the will of the House of Commons. Fuirthermore, since 1945, there has been the Salisbury Convention that the House of Lords will not oppose a measure that was specifically mentioned in the last election manifesto of the political party forming the Government.

The House of Lords is an utterly bizarre institution that has no parallel anywhere in the democratic world. Indeed the only other country with an unelected second chamber is Lesotho. The explanation for the unusual nature of the Lords goes back to the beginning of this essay: the British political system has evolved very slowly and peacefully and it is not totally logical or democratic.

There is no fixed number of members in the House of Lords, but currently there are just over 780 members - many more than in the House of Commons, more than the combined houses of the American Congress or the Indian Parliament (although both of these nations have a federal system), and the second biggest legislative body in the world (after the Chinese National People's Congress which is effectively a rubber-stamping body). The number was actually halved to 666 in the reforms of 1999 but, since then, succesive Prime Ministers have been adding new life peers much faster than members are dying. Indeed the last (Colaition) Government added over 100. Ironically the size of the House of Lords continues to rise at the same time as the House of Commons has legislated to reduce its size.

Historically most members of the House of Lords have been what we called hereditary peers. This meant that years ago a king or queen nominated a member of the aristocracy to be a member of the House and, since then, the right to sit in the House has passed through the family from generation to generation. Clearly this is totally undemocratic and the last Labour Government abolished the right of all but 92 of these hereditary peers to sit in the House.

Almost all the other members of today's House of Lords are what we call life peers. This means that they have been chosen by the Queen, on the advice of the Government, to sit in the House for as long as they live, but afterwards no member of their family has the right to sit in the House. Almost 200 are former Members of Parliament. Others are distinguished figures in fields such as education, health and social policy.

A small number of other members - 26 - are archbishops and bishops of the Church of England. The archbishops of Canterbury and York and the bishops of London, Durham and Winchester automatically take seats in the Lords, while the further 21 seats are allocated on the basis of length of service. Iran is the only other country in the world that provides automatic seats for senior religious figures in its legislature.

At the last count (1999), two-thirds of peers were aged over 65 and 15% were aged over 80. There is no retirement age.

There is nowhere near sufficient seating capacity in the chamber of the House of Lords for all the peers. Members do not sit at desks (like most legislatures) but on long, red-covered benches and there is only seating capacity for 230 peers out of the total of 774. Even on a 'whipped' vote, a couple of hundred peers will not turn up.

House of Lords reform is unfinished business. The Parliament Act of 1911 first raised the prospect of an elected upper house but it has still not happened. There is a cross-party consensus that it should become a mainly elected body, although there is as yet no agreement on the details of the next stage of reform.

Much of the work of Parliament is done in Committees rather than on the floor of the chamber. The House of Commons has two types of committee:

Select Committees are appointed for the lifetime of a Parliament, 'shadow' the work of a particular Government Department, conduct investigations, receive written and oral evidence, and issue reports. Membership is made up only of backbenchers and reflects proportionately the balance of the parties in the Commons.

General Committees (previously known as Standing Committees) are temporary bodies, most of them Public Bill Committees formed to examine the detail of a particular piece of proposed legislation and consider amendments to the Bill. Membership includes Government and Opposition spokepersons on the subject matter of the Bill and overall membership reflects proportionately the balance of the parties in the Commons.

The House of Lords only has Select Committees (it does not need Standing Committees because the details of Bills are considered on the floor of the chamber).

Finally there are some Joint Committees of the Commons and the Lords.

Discussion and debate involve quite a gladiatorial or confrontational approach. This is reflected in the physical shape of the chambers. Whereas most legislatures are semi-circular, both the House of Commons and the House of Lords are rectangular with the Government party sitting on one side and the Opposition parties sitting on the other side. The House of Lords alone has cross-benches for independent peers. It is quite normal for speakers in debates to be interrupted by other members, especially of another party, and, in the Commons, cheering and jeering is a regular occurrence.

In the Commons, there is a Prime Minister's Question (PMQ) Time for 30 minutes at 12 noon every Wednesday. Questions can be asked on any subject. This is frequently a heated affair with the Leader of the Opposition trying to embarrass the Prime Minister and it is the one part of the week's proceedings guaranteed to attract the interest of the media. In his book "A Journey", former Prime Minister Tony Blair wrote: "PMQs was the most nerve-wracking, discombobulating, nail-biting, bowel-moving, terror-inspiring, courage-draining experience in my prime ministerial life, without question."

The Government is normally assured of a majority in the House of Commons for any measure or vote. This is mainly because in the Commons there is a strong 'whipping' system in which political parties tell their members how to vote on every significant division though a weekly set of instructions. The importance of actually being present to vote in the manner instructed depends on whether the 'whip' is one-line, two-line or - the most serious - three-line. Even when there is a rebellion by members of the majority party, the Government usually obtains its wish because all Ministers and their Parliamentary Private Secretaries (PPSs) are required to vote for the Government or resign their Ministerial or PPS position. This is called 'the payroll vote' (although PPS are not actually paid to be a PPS) and currently around 120 MPs or 22% of the Commons make up this block vote.

The official record of the proceedings of the Commons and the Lords is called Hansard. The press and broadcasters are present all the time and live audio and visual broadcasting can take place at any time.

THE LEGISLATIVE PROCESS

In the British political system, almost all legislation is proposed by the Government and much of it comes from promises made in the manifesto of the relevant political party at the last election. At the beginning of each annual session of the Parliament, the main Bills to be considered are announced by the Queen in a speech opening that year's session of Parliament.

All legislation has to be approved by both Houses of Parliament.

In each House of Parliament, a proposed piece of legislation - called a Bill - goes through the following stages:

First Reading - the Bill is introduced with simply a reading by a Minister of the long title of the Bill

Second Reading - the general principles of the Bill are debated by all the members of the House and a formal vote is taken

Committee Stage - each clause and schedule of the Bill, plus amendments to them and any new clauses or schedules, is examined in detail, in the Commons by a small, specially chosen group of members meeting as Public Bill Committee or in the Lords by the members as a whole on the floor of the House

Report Stage - the changes made to the Bill in the Committee are reported to and debated by the whole House which is invited to consider the Bill as a whole, approve the changes by the Committee, and consider any further proposed changes that might be suggested

Third Reading - the final version of the Bill is considered by the whole House in a short debate (in the Commons without the facility for further amendments)

Royal Assent - the Crown gives assent to the Bill which then becomes an Act, the provisions becoming law either immediately or at a date specified in the Act or at a date specified by what is called a Commencement Order

Several points are worth noting about the legislative process:

Under normal circumstances, all these stages must be completed in both Houses in one session of Parliament; otherwise the process must begin all over again.

Debates on most Bills are timetabled through a programme motion (when Government and Opposition agree) or an allocation of time motion which is popularly known as a 'guillotine' motion (when Government and Opposition do not agree).

As well as almost all legislation coming from the Government, almost all successful amendments originate from the Government.

The House of Lords has much more limited legislative powers than the House of Commons. Money Bills can only be initiated in the Commons and the Lords can only reject legislation from the Commons for one year. Furthermore there is a convention - called the Salisbury Convention - that the Lords does not block legislation in fulfillment of the election manifesto of the elected Government.

The idea of political parties first took form in Britain and the Conservative Party claims to be the oldest political party in the world. Political parties began to form during the English civil wars of the 1640s and 1650s. First, there were Royalists and Parliamentarians; then Tories and Whigs. Whereas the Whigs wanted to curtail the power of the monarch, the Tories - today the Conservatives - were seen as the patriotic party.

Today there are four major political parties in the British parliamentary system:

The Conservative Party (frequently called the Tories) - the centre-Right party, currently led by David Cameron, which since 2010 has been in Government either in coalition (2010-2015) or alone (since 2015)

The Labour Party - the centre-Left party, led by Ed Miliband until May 2015, which was last in Government from 1997 to 2010

The Scottish National Party - the party supporting Scottish independence, which is led by Nicola Sturgeon

The Liberal Democrat Party (known as the Lib Dems) - the centrist, libertarian party, led by Nick Clegg until May 2015, which was the junior member of the Coalition Government of 2010-2015

In recent years, Britain has seen the rise of the UK Independence Party (UKIP) led by Nigel Farage until May 2015, which was formed in 1993 but achieved some spectacular performances in local and European elections May 2014. In the general elwection of May 2015, it won 12.6% of the vote but only one seat at Westminster.

In addition to these five main parties, there are some much smaller UK parties (notably the Green Party) and some parties which operate specifically in Wales (Plaid Cymru) or Northern Ireland (such as Sinn Fein for the nationalists and the Democratic Unionist Party for the loyalists).

Each political party chooses its leader in a different way, but all involve all the Members of Parliament of the party and all the individual members of that party. By convention, the leader of the political party with the largest number of members in the House of Commons becomes the Prime Minster (formally at the invitation of the Queen).

Political parties are an all-important feature of the British political system because:

The three main UK political parties in the UK have existed for a century or more and have a strong and stable 'brand image'.

It is virtually impossible for someone to be elected to the House of Commons without being a member of an established political party.

All political parties strongly 'whip' their elected members which means that, on the vast majority of issues, Members of Parliament of the same party vote as a 'block'.

Having said this, the influence of the three main UK political parties is not as dominant as it was in the 1940s and 1950s because:

The three parties have smaller memberships than they did, since voters are much less inclined to join a political party.

The three parties secure a lower overall percentage of the total vote, since smaller parties between them now take a growing share of the vote.

Voters are much less 'tribal', not supporting the same party at every election, and much more likely to 'float, voting for different parties at successive elections.

The ideological differences between the parties are less than they were, with the parties adopting more 'pragmatic' positions on many issues.

In the past, class was a major determinant of voting intention in British politics, with most working class electors voting Labour and most middle class electors voting Conservative. These days, class is much less important because:

Working class numbers have shrunk and now represent only 43% of the electorate.

Except at the extremes of wealth, lifestyles are more similar.

Class does not determine voting intention so much as values, trust, competence and (in Scotland) nationalism).

In the British political system, there is a broad consensus between the major parties on:

the rule of law

the free market economy

the National Health Service (NHS)

UK membership of European Union and NATO

The main differences between the political parties concern:

how to tackle poverty and inequality

the levels and forms of taxation

the extent of state intervention in the economy

the balance between collective rights and individual rights

the UK's relationship to the European Union

THE U.K. GOVERNMENT

All Government Ministers have to be a member of either the House of Commons (most of them) or the House of Lords (the remainder of them) and every Government Department will have at least one Minister in the Lords, so that the Department can speak in either House as necessary. The number of Ministers varies from administration to administration, but typically there will be around 120, the 20 or so most senior being Cabinet Ministers. The Ministerial and Other Salaries Act, passed in 1975, limits prime ministers to 109 ministerial salaries being paid at any one time with a maximum of 95 ministers in the House of Commons.

Historically most British governments have been composed of ministers from a single political party which had an overall majority of seats in the House of Commons and the 'first-past-the-post' (FPTP) electoral system greatly facilitates and indeed promotes this outcome. However, occasionally there have been minority governments or coalition governments.

For five years, the UK had its first coalition government in 65 years when, in May 2010, the Conservatives went into coalition with the Liberal Democrats because in the General Election they did not secure a majority of the seats. In this coalition, the Lib Dems had 17 ministers led by the Deputy Prime Minister Nick Clegg.

However, at the General Election of May 2015, the Conservative Party won an overall majority and the normal arrangement resumed of all Ministers coming from the same party.

The Prime Minister

The UK does not have a President. Constitutionally the head of state is the monarch who is a hereditary member of the Royal Family. However, the monarch has very few formal powers and stays above party politics. He or she receives a weekly oral report from the Prime Minister, a tradition which began with King George I in 1714 because this German had struggled to follow the English deliberations of his Cabinet.

Therefore, in practice, the most important person in the British political system is the Prime Minister. The first modern Prime Minister was Sir Robert Walpole who served from 1721-1742, so the current PM - David Cameron - is the 53rd (and, on first taking office, the youngest since 1812, a few months younger than when Tony Blair became PM in 1997). In theory, the Prime Minister simply choses the ministers who run Government departments and chairs the Cabinet - the collection of the most senior of those Ministers. In practice, however, the Prime Minister is a very powerful figure and increasingly has been behaving much like a president in other political systems, especially in the area of foreign policy.

The official residence of the Prime Minister is at 10 Downing Street in central London - a location I have visited about a dozen times - and the country residence of the Prime Minister is at Chequers in Buckinghamshire.

One British Prime Minister has been assassinated: Spencer Perceval was shot dead in the House of Commons in 1812.

The Treasury - In most countries, this would be called the Ministry of Finance. It is responsible for the raising of all taxes and the control of all government expenditure plus the general management of the economy. The head of the Treasury is called the Chancellor of the Exchequer and is currently George Osborne (who, on taking office, was the youngest Chancellor for more than 180 years).

The Home Office - In most countries, this would be called the Ministry of the Interior. It is responsible for criminal matters, policing, and immigration. The Head of the Home Office is called the Home Secretary and is currently Teresa May.

The Foreign and Commonwealth Office - In most countries, this would be called the Ministry of Foreign Affairs. It is responsible for all international relationships, especially membership of the European Union. The head of the Foreign Office is called the Foreign Secretary and is currently Philip Hammond.

Many other UK Government Departments are similar to those in other countries and cover subjects such as education, health, transport, industry, and justice. However, there are also small departments for Scotland, Wales and Northern Ireland.

When talking about the British Government, the media will often use the term Whitehall because a number of Government Departments are located along a central London street very close to Parliament called Whitehall.

Government Ministers

All Government Departments are run by Ministers who are either Members of the House of Commons or Members of the House of Lords. There are three classes of Minister:

Secretary of State - This is usually the head of a Department.

Minister of State - This is a middle-ranking minister.

Parliamentary Under-Secretary of State - This is the most junior class of minister.

The Prime Minster and all the Secretaries of State together comprise an executive body of government called the Cabinet. The Cabinet meets usually once a week on Tuesday morning. Cabinet meetings are confidential and all members are bound by any decision that it takes in a practice called collective responsibility. An extensive system of Cabinet Committees considers matters either before they go to Cabinet or (more usually) instead of them going to Cabinet.

Although all Ministers are appointed by the Prime Minster and report to him, ultimately all Ministers are accountable to Parliament:

About once a month, they have to face questions in the House of Commons about the work of the Department.

Each government department has a special committee of the House of Commons which watches the work of that Department.

Any government initiative or important statement concerning a Department must be the subject of an appearance in the House of Commons by a minister from that Department.

Each Secretary of State is able to appoint a couple of political advisers  formally known as Special Advisers  to serve him or her. I was a Special Adviser to Merlyn Rees in the Northern Ireland Office from 1974-1976 and in the Home Office from 1976-1978, while my son Richard was a Special Adviser to Ruth Kelly in the Department for Education & Skills in 2005 and a Special Adviser to Douglas Alexander at the Department for International Development in 2009-2010.

But Special Advisers are simply advisers. They have no line management responsibilities in respect of the staff of the Department. Besides these tiny number of Special Advisers, Government Departments are run by civil servants who are recruited in a totally open manner and serve governments of any political parties. The independence and professionalism of the British civil service are fundamental features of the British political system. My son Richard once worked as a civil servant in what was then the Department of Trade & Industry and my half-brother Chris was an official in the Treasury for five years.

DEVOLVED GOVERNMENT

The UK has a devolved system of government, but this is categorically not a system of federal government such as in the United States [click here] or Australia [click here], partly because less than a fifth of the citizens of the UK are covered the three bodies in question and partly because the three bodies themselves have different powers from one another.

The three devolved administrations are:

The Scottish Parliament

This came into operation in May 1999 and covers the 5M citizens of Scotland. It has 129 members elected by a system of proportional representation known as the mixed member system. As a result, 73 members represent individual geographical constituencies elected by the 'first past the post' (FPTP) system, with a further 56 members returned from eight additional member regions, each electing seven members. All members are elected for four-year terms.

The Scottish Parliament meets in Holyrood, Edinburgh. It has legislative powers over those matters not reserved to the UK Parliament and it has limited tax-raising powers.

In the election of May 2011, for the first time a single political party gained an overall majority of the seats in the Scottish Parliament. That party was the Scottish National Party and its victory enabled it to require the UK Government to permit the holding of a referendum on Scottish independence.

The referendum was held on 18 September 2014 and, on an astonishing turnout of 85%, the 'no' vote won a decisive victory by 55% to 45%. However, in the final week of the two-year referendum campaign, the three major parties in the UK Parliament agreed that, if the Scots voted 'no', there would be an early transfer of substantial extra powers to the Scottish Parliament. This is now the subject of fierce political debate because of the implications for the other nations in the UK and for the UK Parliament itself.

This came into operation in May 1999 and covers the 3M citizens of Wales. It has 60 members elected by a system of proportional representation known as the mixed member system. As a result, 40 members represent individual geographical constituencies elected by the 'first past the post' (FPTP) system, with a further 20 members returned from five additional member regions, each electing four members. All members are elected for four-year terms.

It meets in the Senedd, Cardiff. When first created, the Assembly had no powers to initiate primary legislation. However, since 2006, the Assembly has powers to legislate in some areas, though still subject to the veto of the Westminster Parliament. The Assembly has no tax-varying powers. The Welsh Assembly, therefore, has less power than either the Scottish Parliament or the Northern Ireland Assembly because - unlike Scotland and Northern Ireland - Wales does not have a separate legal system from England.

The present version of the Assembly came into operation in May 2007 and covers the 1.5M citizens of Northern Ireland. It has 108 members - six from each of the 18 Westminster constituencies - elected by a system of proportional representation known as the single transferable vote (STV).

It meets in the Parliament Building, Belfast. It has legislative powers over those matters not reserved to the UK Parliament, but it has no tax-raising powers.

A First Minister and a Deputy First Minister are elected to lead the Executive Committee of Ministers. As a result of the sectarian division in Northern Ireland, the two must stand for election jointly and to be elected they must have cross-community support by the parallel consent formula, which means that a majority of both the Members who have designated themselves Nationalists and those who have designated themselves Unionists and a majority of the whole Assembly, must vote in favour. The First Minister and Deputy First Minister head the Executive Committee of Ministers and, acting jointly, determine the total number of Ministers in the Executive.

The British judicial branch is extremely complex. Unlike most countries which operate a single system of law, the UK operates three separate legal systems: one for England and Wales, one for Scotland, and one for Northern Ireland. Although bound by similar principles, these systems differ in form and the manner of operation.

Currently a process of reform is in operation.

The Lord Chancellor's office - which for 1,400 years maintained the judiciary - has now been replaced by the Ministry for Justice which administers the court system. A Judical Appointments Commission has been set up to advise the head of the MoJ on the appointment of new judges.

The Appellate Committee of the House of Lords - previously the highest court in the land - was, by way of the Constitutional Reform Act 2005, replaced by the Supreme Court in October 2009 to allow the judiciary to operate in total independence from the Government. The Supreme Court is now the ultimate court of appeal in all legal matters other than criminal cases in Scotland. It consists of 12 judges and sits in the Middlesex Guildhall in Parliament Square.

The UK does not have its own Bill of Rights. However, since 1951 it has been a signatory to the European Convention on Human Rights (part of the Council of Europe) and since 1966 it has allowed its citizens the right of individual petition enabling them to take the government to the European Court of Human Rights in Strasbourg. The last Labour Government incorporated the provisions of the European Convention into UK domestic law in 2000, so that citizens can now seek to have the provisions enforced in domestic courts.

CIVIL SOCIETY

One cannot explain a liberal democracy such as the United Kingdom simply by talking about the formal political and governmental institutions, any more than one can understand fish without talking about water.

Democratic government cannot operate without a strong civil society to support it and hold political and governmental bodies to account. The special history of the UK - involving gradual changes over long periods - has created a subtle but effective civil society that outsiders often find a little difficult to understand. So it is useful to list some of the more important elements of such a civil society:

Bill of Rights - Although Britain does not have a written constitution, it does have a Bill of Rights because it is a signatory to the European Convention on Human Rights which was drawn up by a body called the Council of Europe. The European Convention is part of the domestic law so that it can be enforced in the domestic courts as well as in the European Court of Human Rights.

Independent judiciary - British judges are appointed through an independent process and operate totally independently of government. They can find that a Government Minister has acted against a law of the UK Parliament or a Directive of the European Union or against the European Convention and require the Minister to change his or her actions.

A free media - As long as they are not being libelous, newspapers, radio and television can say what they want about the Parliament, the Government and politicians. An important new development is the Internet. Web sites and blogs can say what they want about politicians and political issues. I have a web site and a blog and I often write about political issues. There is no need in the UK to register a newspaper or web site or to obtain permission to run it.

Freedom of information legislation - Britain has a Freedom of Information Act which is a piece of legislation that obliges national government, local government and most public bodies to provide any information requested by an citizen. The only exceptions are things like information which concern national security, commercial confidentiality, or the private matters of citizens.

Trade unions - About a quarter of workers in Britain are members of trade unions representing different occupational groups or industries. These trade unions are totally independent of government and employers. I was a national trade union official for 24 years and believe strongly in independent trade unions.

Pressure groups - Britain has lots and lots of organisations that campaign publicly on political issues such as poverty, pensions, and the environment. They perform an invaluable role in putting forward ideas and holding politicians to account.

Charities and voluntary groups - Similarly we have lots and lots of organisations that do some of the things that government does as well such as running schools and hospitals, looking after the poor and old, and cleaning up the environment.

CONSTITUTIONAL AND POLITICAL REFORM

Compared to many other democracies, institutional and procedural reform in the British political system has been very slow, gradual and piecemeal. However, there has been a growing movement for more reform, starting with the actual running of the House of Commons:

Since the election of (Conservative MP) John Bercow as Speaker of the House of Commons, there have been many more occasions of the use of the Urgent Question (UQ). This is a device which allows any Member of Parliament on any sitting day to petition the Speaker to demand that a Government Department supplies a Minister to make a statement on some issue or matter that has arisen very suddenly.

Eight weeks before the May 2010 General Election, the House of Commons embraced the election of the Deputy Speakers, the whole House election of Select Committee Chairs, the whole party caucus election of Select Committee members, and the creation of a House Backbench Business Committee.

In November 2013, the Speaker of the House of Commons John Bercow announced the formation of a novel type of inquiry, a Speaker’s Commission, to examine the whole issie of Digital Democracy. This exercise started in early 2014 and reported in early 2015.

The appetite for constitutional change became much stronger in the aftermath of the May 2009 scandal over the expenses of Members of Parliament. Then the formation in May 2010 of a Conservative/Liberal Democrat Coalition Government opened up new possibilities for change with a number of specific measures set out in the agreement between the parties establishing the new government. However, actual progress has been limited.

The changes on the agenda of the previous Coalition Government were as follows:

Fixed term parliaments - In the past, elections to the House of Commons had to be held within five years of the previous General Election but the Prime Minister had complete discretion over the actual date which was often the subject of considerable speculation and frequently a year or more before an election was legally necessary. The coalition parties agreed to the establishment of five year fixed-term parliaments and the necessary legislation has now been enacted. Therefore, subject to at an earlier time either a vote of no confidence in the Government or a two-thirds majority vote, each General Election will now be held on the first Thursday of May five years after the previous election.

A new electoral system for the House of Commons - Britain is unusual in Europe in having an electoral system which is 'first-past-the-post' (FPTP) and there are advocates for a system of proportional representation (PR), versions of which are already used for elections to the Scottish Parliament, the Welsh Assembly and the Northern Ireland Assembly and for British elections to the European Parliament. As a vital component of the coalition agreement, legislation was carried to enable a referendum to be held on an electoral system called the alternative vote (AV) which enables the voter to number candidates in order of preference and requires a winning candidate to secure more than 50% of the votes which, if not achieved on the first count, is achieved through successive withdrawal of the lowest-polling candidate and redistribution of that candidate's preferences. The referendum - only the second UK-wide referendum in its history - was held on 5 May 2011, but the current electoral system was supported by a margin of more than two to one (I voted for a move to AV).

Fewer and more equal sized constituencies - Currently the House of Commons has 650 seats; the Coalition Government intended to cut this to 600. Currently the number of electors in each Parliamentary constituency varies quite considerably; the Coalition Government legislated that no constituency should be more than 5% either larger or smaller than a national average of around 76,000 electors (which could eliminate some 40 Labour-held seats). The Government included these measures in the Referendum Bill on electoral reform and it was intended that the new constituencies would come into effect at the General Election in 2015. However, although the Bill is now on the statute book, the new constituencies did not become operative at the General Election following a Commons vote of 334 to 292 against early implementation when the Liberal Democrats joined with Labour to block implementation in retaliation for Conservative MPs failing to support the reform of the House of Lords strongly favoured by the Lib Dems.

Election of the House of Lords - At present, no member of the upper house is actually elected; most are appointed on the nomination of party leaders with a small number remaining from the originally much larger group of hereditary peers. The Queen's Speech of May 2012 announced that there would be a Bill on Lords reform in that session of Parliament. The latest proposal for reform comes from a Joint Committee of the two houses which recommended a 450-seat chamber with peers elected for 15 years in elections to be held every five years. Of these, 80% would be elected by a form of proportional representation with 20% appointed by an independent body. In fact, neither the Commons (especially the Conservative Party) nor the Lords is keen on reform for very different reasons (MPs do not want the Lords to gain more legitimacy and nominated peers do not want to be replaced by elected representatives). In the summer of 2012, the Prime Minister announced that he could not deliver Conservative support for a reform measure which was therefore withdrawn to the intense anger of the Liberal Democrats who very much support reform.

More power to backbench Members of Parliament - In the British political system, the party in Government has considerably more power in the legislature than the Opposition parties and in all the political parties the whips have considerable power over backbenchers. Ordinary MPs could be given more influence by measures such as more independent and stronger all-party Select Committees, more unwhipped votes (especially during the Committee Stage of Bills), more support for Private Members' Bills (those initiated by backbenchers rather than Ministers), more power to scrutinise Government spending, and a new power to subject ministers to confirmation hearings.

The power to force a by-election - Currently a by-election occurs only when an MP dies or resigns or is sentenced to more than one year in prison. In the last Parliament, the Government put forward legislation to make the recall of an errant MP easier. The new Act requires that, if an MP is convicted of an offence and sentenced to a custodial sentence of 12 months or less or if the Commons orders the MP's suspension for at least 28 sitting days (or 28 calendar days), then the MP's constituents will have the opportunity to sign a recall petition calling for a by-election. It will require at least 10% of constituents to sign the petition for a by-election to be held.

More devolution nationally and locally - The Scottish Parliament, the Welsh Assembly and the Northern Ireland Assembly all have devolved powers and all of them want more, while many local authorities feel that, over past decades, their powers have been eroded by the national parliament. Some believe that a revitalisation of the British political system requires more devolution of power. The main political parties in the UK Parliament had already agreed to the implementation of the Calman Commission proposals on further Scottish devolution and the offer of a referendum on further Welsh devolution. However, in the final week of the Scottish independence referendum campaign, the three major parties in the UK Parliament agreed that, if the Scots voted 'no' (as they did), there would be an early transfer of substantial extra powers to the Scottish Parliament. This is now the subject of fierce political debate because of the implications for the other nations, regions and cities in the UK and for the UK Parliament itself.

Use of e-petitions - Citizens are encouraged to use the Government web site to create electronic petitions to promote specific political reforms. It might be that the most popular petition will be drafted as a Bill and presented to Parliament, while those petitions that reach a certain level of support - probably 100,000 signatures - will be guaranteed a debate in the House of Commons.

Funding and lobbying - All political parties find it difficult to raise the funding necessary to promote their messages and run their election campaigns and, in practice, the Labour Party receives much of its funding from a small number of trade unions and the Conservative Party is backed mainly by large companies. It has been argued that democracy would be better served and parties could be more independent if there was public funding of political parties with the actual level of funding depending of some combination of candidates and votes. The parties have agreed to pursue a detailed agreement on limiting donations and reforming party funding in order to remove 'big money' from politics. Also the parties intend to tackle lobbying through introducing a statutory register of lobbyists.

Candidates for further change would include the following proposals:

A wider franchise - At present, every citizen over 18 can vote but it has been suggested that the voting age should be lowered to 16. In the Coalition Government, the Liberal Democrats supported such an extension to the franchise but the Conservatives opposed it. Meanwhile the Scottish Nationalist Government allowed 16 and 17 year olds to vote in the 2014 referendum on Scottish independence.

A wider process for selecting Parliamentary candidates - Today candidates are selected by meetings of members of the political party that the candidate will represent in a future election, but it has been proposed that the process could be opened up to anyone in the relevant constituency who has declared themselves a supporter of that party, a process something like the primaries in the United States.

A more modern culture for the Commons - Many of the traditions and much of the language of the Commons date back centuries and reformers argue that it is time for change to make the proceedings more accessible and acceptable to the public and electorate. The sort of changes mooted are no ceremonial dress for Commons staff, reform of terms such as "My right honourable friend", and a less gladiatorial version of Prime Minister's Questions.

Limits on the Royal Prerogative - At the moment, the Prime Minister alone can exercise powers which once used to belong to the monarch, such as the right to apppoint certain judges and bishops, the signing of international treaties, and the declaring of war, but this could be changed so that Parliament has to decide such matters.

A domestic Bill of Rights - The UK has a Bill of Rights but it is the European Convention on Human Rights which, since 2000, has been part of the domestic law and therefore enforcable in national courts as well as the European Court. Some people believe that Britain should draft its own specific Bill of Rights. A Bill of Rights Commission, chaired by Sir Leigh Lewis, met for 18 months to consider this matter and reported in December 2012 when it was utterly unable to reach any sort of consensus. However, the current Conservative Government would like to remove the European Convention from the UK's domestic law and substitute it with a British Bill of Rights.

A written constitution - For historical reasons, the UK is one of only three countries in the world not to have a written constitution (the others are New Zealand and Israel). The most radical proposal for constitutional change - supported especially by the Liberal Democrat Party - is that the country should now have a formal written constitution, presumably following some sort of constitutional convention and possibly a referendum.

So, at the time of the General Election of May 2010, the scene seemed set for more change than for many decades but, in reality, most of the measures discussed at the time of the Coalition Agreement floundered. Nevertheless, as a consequence of the 2014 referendum on Scottish independence, there is now a more fundamental debate about the British constitution than at any other time in living memory.